On the deflecting wrinkle in the lower molars of Malawians derived from pureblooded Negroid racial stock

Abstract

The occurrence of the deflecting wrinkle on the lower molars was studied in a pureblooded Negroid population from Malawi in East-central Africa. Samples comprised 65 males and 67 females, in which observations were performed using dental hard plaster casts. Deflecting wrinkles were classified into nine classes according to the criteria of Hanihara et al. (1964). The chi-square test showed no significant difference in occurrence of the trait between sexes. The occurrence of the deflecting wrinkle on first lower molars in the Malawians was lower than that in Mongoloid populations except for the Ainu. The trait, therefore, could be valid as a part of the“Mongoloid dental complex”. However, this feature was clearly observed more frequently in the Malawians than in the Japanese. Taking also into consideration the fact that the frequency of the trait in Malawians falls within the low range of variation of the Mongoloid frequency in the first lower molars, further detailed investigations to evaluate the exact racial diagnostic value of the trait is still desirable.